This document relates to a new and improved convertible door assembly having (a) a full-door configuration with a window that may be raised and lowered and (b) two different abbreviated-door configurations for beautiful days when an open air experience is desired. In the past, it has been necessary to provide a motor vehicle with two, interchangeable doors in order to provide door configurations of the type described. This convertible door assembly eliminates the need for two separate doors and thus represents a significant advance in the art.